The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. For example, conventional photoresist layers comprise a base, which is not photosensitive. Thus, after an exposure process, exposed areas of a photoresist layer may exhibit less than desirable acid distribution contrast and base distribution contrast. This leads to lower pattern contrast, resulting in poor pattern profiles and/or poor resolution, particularly as pattern features continue to decrease in size.
Conventional methods for improving resolution usually include using a quencher, photo decomposable base (PDB), and a photo-acid generator (PAG) in the photoresist layer. The PAG generates an acid after exposure. The quencher is a base molecule that can neutralize the acid to quench a chemically amplified reaction (CAR) in the exposure area. The quencher can neutralize excess acid and prevent acid from diffusing to unexposed areas. However, bases in the exposure area are typically not favored because they can consume protons that are needed in the CAR. The PDB displays a base in the unexposed area and decomposes to a neutral species or a weak acid when exposed in the exposed area. The PDB can maintain the concentration of acid in the exposed areas. However, a PDB can compete with the PAG and increase the dose energy.
Accordingly, what is needed is a method and photoresist material for manufacturing an integrated circuit device that addresses the above stated issues.